4 The following is a consolidated list of the kernel parameters as implemented
5 (mostly) by the __setup() macro and sorted into English Dictionary order
6 (defined as ignoring all punctuation and sorting digits before letters in a
7 case insensitive manner), and with descriptions where known.
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
12 modprobe usbcore blinkenlights=1
14 Module parameters for modules that are built into the kernel image
15 are specified on the kernel command line with the module name plus
16 '.' plus parameter name, with '=' and value if appropriate, such as:
18 usbcore.blinkenlights=1
20 This document may not be entirely up to date and comprehensive. The command
21 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22 module. Loadable modules, after being loaded into the running kernel, also
23 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24 parameters may be changed at runtime by the command
25 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
27 The parameters listed below are only valid if certain kernel build options were
28 enabled and if respective hardware is present. The text in square brackets at
29 the beginning of each description states the restrictions within which a
30 parameter is applicable:
32 ACPI ACPI support is enabled.
33 AGP AGP (Accelerated Graphics Port) is enabled.
34 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
37 AVR32 AVR32 architecture is enabled.
38 AX25 Appropriate AX.25 support is enabled.
39 BLACKFIN Blackfin architecture is enabled.
40 DRM Direct Rendering Management support is enabled.
41 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
42 EFI EFI Partitioning (GPT) is enabled
43 EIDE EIDE/ATAPI support is enabled.
44 FB The frame buffer device is enabled.
45 HW Appropriate hardware is enabled.
46 IA-64 IA-64 architecture is enabled.
47 IMA Integrity measurement architecture is enabled.
48 IOSCHED More than one I/O scheduler is enabled.
49 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
50 ISAPNP ISA PnP code is enabled.
51 ISDN Appropriate ISDN support is enabled.
52 JOY Appropriate joystick support is enabled.
53 LIBATA Libata driver is enabled
54 LP Printer support is enabled.
55 LOOP Loopback device support is enabled.
56 M68k M68k architecture is enabled.
57 These options have more detailed description inside of
58 Documentation/m68k/kernel-options.txt.
59 MCA MCA bus support is enabled.
60 MDA MDA console support is enabled.
61 MOUSE Appropriate mouse support is enabled.
62 MSI Message Signaled Interrupts (PCI).
63 MTD MTD (Memory Technology Device) support is enabled.
64 NET Appropriate network support is enabled.
65 NUMA NUMA support is enabled.
66 GENERIC_TIME The generic timeofday code is enabled.
67 NFS Appropriate NFS support is enabled.
68 OSS OSS sound support is enabled.
69 PV_OPS A paravirtualized kernel is enabled.
70 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
71 PARISC The PA-RISC architecture is enabled.
72 PCI PCI bus support is enabled.
73 PCIE PCI Express support is enabled.
74 PCMCIA The PCMCIA subsystem is enabled.
75 PNP Plug & Play support is enabled.
76 PPC PowerPC architecture is enabled.
77 PPT Parallel port support is enabled.
78 PS2 Appropriate PS/2 support is enabled.
79 RAM RAM disk support is enabled.
80 ROOTPLUG The example Root Plug LSM is enabled.
81 S390 S390 architecture is enabled.
82 SCSI Appropriate SCSI support is enabled.
83 A lot of drivers has their options described inside of
85 SECURITY Different security models are enabled.
86 SELINUX SELinux support is enabled.
87 SERIAL Serial support is enabled.
88 SH SuperH architecture is enabled.
89 SMP The kernel is an SMP kernel.
90 SPARC Sparc architecture is enabled.
91 SWSUSP Software suspend (hibernation) is enabled.
92 SUSPEND System suspend states are enabled.
93 FTRACE Function tracing enabled.
94 TS Appropriate touchscreen support is enabled.
95 USB USB support is enabled.
96 USBHID USB Human Interface Device support is enabled.
97 V4L Video For Linux support is enabled.
98 VGA The VGA console has been enabled.
99 VT Virtual terminal support is enabled.
100 WDT Watchdog support is enabled.
101 XT IBM PC/XT MFM hard disk support is enabled.
102 X86-32 X86-32, aka i386 architecture is enabled.
103 X86-64 X86-64 architecture is enabled.
104 More X86-64 boot options can be found in
105 Documentation/x86/x86_64/boot-options.txt .
106 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
108 In addition, the following text indicates that the option:
110 BUGS= Relates to possible processor bugs on the said processor.
111 KNL Is a kernel start-up parameter.
112 BOOT Is a boot loader parameter.
114 Parameters denoted with BOOT are actually interpreted by the boot
115 loader, and have no meaning to the kernel directly.
116 Do not modify the syntax of boot loader parameters without extreme
117 need or coordination with <Documentation/x86/i386/boot.txt>.
119 There are also arch-specific kernel-parameters not documented here.
120 See for example <Documentation/x86/x86_64/boot-options.txt>.
122 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
123 a trailing = on the name of any parameter states that that parameter will
124 be entered as an environment variable, whereas its absence indicates that
125 it will appear as a kernel argument readable via /proc/cmdline by programs
126 running once the system is up.
128 The number of kernel parameters is not limited, but the length of the
129 complete command line (parameters including spaces etc.) is limited to
130 a fixed number of characters. This limit depends on the architecture
131 and is between 256 and 4096 characters. It is defined in the file
132 ./include/asm/setup.h as COMMAND_LINE_SIZE.
135 acpi= [HW,ACPI,X86-64,i386]
136 Advanced Configuration and Power Interface
137 Format: { force | off | ht | strict | noirq }
138 force -- enable ACPI if default was off
139 off -- disable ACPI if default was on
140 noirq -- do not use ACPI for IRQ routing
141 ht -- run only enough ACPI to enable Hyper Threading
142 strict -- Be less tolerant of platforms that are not
143 strictly ACPI specification compliant.
145 See also Documentation/power/pm.txt, pci=noacpi
147 acpi_apic_instance= [ACPI, IOAPIC]
149 2: use 2nd APIC table, if available
150 1,0: use 1st APIC table
153 acpi_sleep= [HW,ACPI] Sleep options
154 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
155 See Documentation/power/video.txt for s3_bios and s3_mode.
156 s3_beep is for debugging; it makes the PC's speaker beep
157 as soon as the kernel's real-mode entry point is called.
158 s4_nohwsig prevents ACPI hardware signature from being
159 used during resume from hibernation.
160 old_ordering causes the ACPI 1.0 ordering of the _PTS
161 control method, wrt putting devices into low power
162 states, to be enforced (the ACPI 2.0 ordering of _PTS is
165 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
166 Format: { level | edge | high | low }
168 acpi_irq_balance [HW,ACPI]
169 ACPI will balance active IRQs
172 acpi_irq_nobalance [HW,ACPI]
173 ACPI will not move active IRQs (default)
176 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
178 Format: <irq>,<irq>...
180 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
181 Format: <irq>,<irq>...
183 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
185 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
186 Format: To spoof as Windows 98: ="Microsoft Windows"
188 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
189 acpi_osi="string1" # add string1 -- only one string
190 acpi_osi="!string2" # remove built-in string2
191 acpi_osi= # disable all strings
193 acpi_serialize [HW,ACPI] force serialization of AML methods
195 acpi_skip_timer_override [HW,ACPI]
196 Recognize and ignore IRQ0/pin2 Interrupt Override.
197 For broken nForce2 BIOS resulting in XT-PIC timer.
198 acpi_use_timer_override [HW,ACPI}
199 Use timer override. For some broken Nvidia NF5 boards
200 that require a timer override, but don't have
203 acpi_backlight= [HW,ACPI]
204 acpi_backlight=vendor
206 If set to vendor, prefer vendor specific driver
207 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
208 of the ACPI video.ko driver.
210 acpi_display_output= [HW,ACPI]
211 acpi_display_output=vendor
212 acpi_display_output=video
215 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
216 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
218 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
219 debug output. Bits in debug_layer correspond to a
220 _COMPONENT in an ACPI source file, e.g.,
221 #define _COMPONENT ACPI_PCI_COMPONENT
222 Bits in debug_level correspond to a level in
223 ACPI_DEBUG_PRINT statements, e.g.,
224 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
225 The debug_level mask defaults to "info". See
226 Documentation/acpi/debug.txt for more information about
227 debug layers and levels.
229 Enable processor driver info messages:
230 acpi.debug_layer=0x20000000
231 Enable PCI/PCI interrupt routing info messages:
232 acpi.debug_layer=0x400000
233 Enable AML "Debug" output, i.e., stores to the Debug
234 object while interpreting AML:
235 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
236 Enable all messages related to ACPI hardware:
237 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
239 Some values produce so much output that the system is
240 unusable. The "log_buf_len" parameter may be useful
241 if you need to capture more output.
243 acpi.power_nocheck= [HW,ACPI]
244 Format: 1/0 enable/disable the check of power state.
245 On some bogus BIOS the _PSC object/_STA object of
246 power resource can't return the correct device power
247 state. In such case it is unneccessary to check its
248 power state again in power transition.
249 1 : disable the power state check
251 acpi_pm_good [X86-32,X86-64]
252 Override the pmtimer bug detection: force the kernel
253 to assume that this machine's pmtimer latches its value
254 and always returns good values.
257 { off | try_unsupported }
258 off: disable AGP support
259 try_unsupported: try to drive unsupported chipsets
260 (may crash computer or cause data corruption)
262 enable_timer_pin_1 [i386,x86-64]
263 Enable PIN 1 of APIC timer
264 Can be useful to work around chipset bugs
265 (in particular on some ATI chipsets).
266 The kernel tries to set a reasonable default.
268 disable_timer_pin_1 [i386,x86-64]
269 Disable PIN 1 of APIC timer
270 Can be useful to work around chipset bugs.
273 Format: <io>,<irq>,<dma>,<dma2>,<type>
276 See header of drivers/scsi/advansys.c.
278 advwdt= [HW,WDT] Advantech WDT
279 Format: <iostart>,<iostop>
281 aedsp16= [HW,OSS] Audio Excel DSP 16
282 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
283 See also header of sound/oss/aedsp16.c.
286 See Documentation/scsi/aha152x.txt.
289 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
292 See Documentation/scsi/aic7xxx.txt.
295 See Documentation/scsi/aic79xx.txt.
297 amd_iommu= [HW,X86-84]
298 Pass parameters to the AMD IOMMU driver in the system.
300 isolate - enable device isolation (each device, as far
301 as possible, will get its own protection
303 share - put every device behind one IOMMU into the
304 same protection domain
305 fullflush - enable flushing of IO/TLB entries when
306 they are unmapped. Otherwise they are
307 flushed before they will be reused, which
310 amd_iommu_size= [HW,X86-64]
311 Define the size of the aperture for the AMD IOMMU
312 driver. Possible values are:
313 '32M', '64M' (default), '128M', '256M', '512M', '1G'
315 amijoy.map= [HW,JOY] Amiga joystick support
316 Map of devices attached to JOY0DAT and JOY1DAT
318 See also Documentation/kernel/input/joystick.txt
320 analog.map= [HW,JOY] Analog joystick and gamepad support
321 Specifies type or capabilities of an analog joystick
322 connected to one of 16 gameports
323 Format: <type1>,<type2>,..<type16>
326 Power management functions (SPARCstation-4/5 + deriv.)
328 Disable APC CPU standby support. SPARCstation-Fox does
329 not play well with APC CPU idle - disable it if you have
330 APC and your system crashes randomly.
332 apic= [APIC,i386] Advanced Programmable Interrupt Controller
333 Change the output verbosity whilst booting
334 Format: { quiet (default) | verbose | debug }
335 Change the amount of debugging information output
336 when initialising the APIC and IO-APIC components.
338 apm= [APM] Advanced Power Management
339 See header of arch/x86/kernel/apm_32.c.
341 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
342 Format: <io>,<irq>,<nodeID>
346 atarimouse= [HW,MOUSE] Atari Mouse
348 atascsi= [HW,SCSI] Atari SCSI
350 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
351 EzKey and similar keyboards
353 atkbd.reset= [HW] Reset keyboard during initialization
355 atkbd.set= [HW] Select keyboard code set
356 Format: <int> (2 = AT (default), 3 = PS/2)
358 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
361 atkbd.softraw= [HW] Choose between synthetic and real raw mode
362 Format: <bool> (0 = real, 1 = synthetic (default))
364 atkbd.softrepeat= [HW]
365 Use software keyboard repeat
369 baycom_epp= [HW,AX25]
372 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
374 See header of drivers/net/hamradio/baycom_par.c.
376 baycom_ser_fdx= [HW,AX25]
377 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
378 Format: <io>,<irq>,<mode>[,<baud>]
379 See header of drivers/net/hamradio/baycom_ser_fdx.c.
381 baycom_ser_hdx= [HW,AX25]
382 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
383 Format: <io>,<irq>,<mode>
384 See header of drivers/net/hamradio/baycom_ser_hdx.c.
386 boot_delay= Milliseconds to delay each printk during boot.
387 Values larger than 10 seconds (10000) are changed to
391 bootmem_debug [KNL] Enable bootmem allocator debug messages.
393 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
394 bttv.radio= Most important insmod options are available as
396 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
397 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
400 See drivers/scsi/BusLogic.c, comment before function
401 BusLogic_ParseDriverOptions().
403 c101= [NET] Moxa C101 synchronous serial card
405 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
406 Sometimes CPU hardware bugs make them report the cache
407 size incorrectly. The kernel will attempt work arounds
408 to fix known problems, but for some CPUs it is not
409 possible to determine what the correct size should be.
410 This option provides an override for these situations.
412 security= [SECURITY] Choose a security module to enable at boot.
413 If this boot parameter is not specified, only the first
414 security module asking for security registration will be
415 loaded. An invalid security module name will be treated
416 as if no module has been chosen.
419 [SECURITY] Disable capabilities. This would normally
420 be used only if an alternative security model is to be
421 configured. Potentially dangerous and should only be
422 used if you are entirely sure of the consequences.
424 ccw_timeout_log [S390]
425 See Documentation/s390/CommonIO for details.
427 cgroup_disable= [KNL] Disable a particular controller
428 Format: {name of the controller(s) to disable}
429 {Currently supported controllers - "memory"}
431 checkreqprot [SELINUX] Set initial checkreqprot flag value.
432 Format: { "0" | "1" }
433 See security/selinux/Kconfig help text.
434 0 -- check protection applied by kernel (includes
435 any implied execute protection).
436 1 -- check protection requested by application.
437 Default value is set via a kernel config option.
438 Value can be changed at runtime via
439 /selinux/checkreqprot.
442 See Documentation/s390/CommonIO for details.
444 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
446 Forces specified clocksource (if available) to be used
447 when calculating gettimeofday(). If specified
448 clocksource is not available, it defaults to PIT.
449 Format: { pit | tsc | cyclone | pmtmr }
451 clocksource= [GENERIC_TIME] Override the default clocksource
453 Override the default clocksource and use the clocksource
454 with the name specified.
455 Some clocksource names to choose from, depending on
457 [all] jiffies (this is the base, fallback clocksource)
459 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
460 pxa_timer,timer3,32k_counter,timer0_1
462 [X86-32] pit,hpet,tsc,vmi-timer;
463 scx200_hrt on Geode; cyclone on IBM x440
471 clearcpuid=BITNUM [X86]
472 Disable CPUID feature X for the kernel. See
473 include/asm-x86/cpufeature.h for the valid bit numbers.
474 Note the Linux specific bits are not necessarily
475 stable over kernel options, but the vendor specific
477 Also note that user programs calling CPUID directly
478 or using the feature without checking anything
479 will still see it. This just prevents it from
480 being used by the kernel or shown in /proc/cpuinfo.
481 Also note the kernel might malfunction if you disable
484 code_bytes [IA32/X86_64] How many bytes of object code to print
489 hpet= [X86-32,HPET] option to control HPET usage
490 Format: { enable (default) | disable | force }
491 disable: disable HPET and use PIT instead
492 force: allow force enabled of undocumented chips (ICH4,
495 com20020= [HW,NET] ARCnet - COM20020 chipset
497 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
499 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
503 ARCnet - COM90xx chipset (memory-mapped buffers)
504 Format: <io>[,<irq>[,<memstart>]]
506 condev= [HW,S390] console device
509 console= [KNL] Output console device and options.
511 tty<n> Use the virtual console device <n>.
515 Use the specified serial port. The options are of
516 the form "bbbbpnf", where "bbbb" is the baud rate,
517 "p" is parity ("n", "o", or "e"), "n" is number of
518 bits, and "f" is flow control ("r" for RTS or
519 omit it). Default is "9600n8".
521 See Documentation/serial-console.txt for more
523 Documentation/networking/netconsole.txt for an
526 uart[8250],io,<addr>[,options]
527 uart[8250],mmio,<addr>[,options]
528 Start an early, polled-mode console on the 8250/16550
529 UART at the specified I/O port or MMIO address,
530 switching to the matching ttyS device later. The
531 options are the same as for ttyS, above.
533 If the device connected to the port is not a TTY but a braille
534 device, prepend "brl," before the device type, for instance
536 For now, only VisioBraille is supported.
538 earlycon= [KNL] Output early console device and options.
539 uart[8250],io,<addr>[,options]
540 uart[8250],mmio,<addr>[,options]
541 Start an early, polled-mode console on the 8250/16550
542 UART at the specified I/O port or MMIO address.
543 The options are the same as for ttyS, above.
546 [HW] Never suspend the console
547 Disable suspending of consoles during suspend and
548 hibernate operations. Once disabled, debugging
549 messages can reach various consoles while the rest
550 of the system is being put to sleep (ie, while
551 debugging driver suspend/resume hooks). This may
552 not work reliably with all consoles, but is known
553 to work with serial and VGA consoles.
555 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
557 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
559 crashkernel=nn[KMG]@ss[KMG]
560 [KNL] Reserve a chunk of physical memory to
561 hold a kernel to switch to with kexec on panic.
563 crashkernel=range1:size1[,range2:size2,...][@offset]
564 [KNL] Same as above, but depends on the memory
565 in the running system. The syntax of range is
566 start-[end] where start and end are both
567 a memory unit (amount[KMG]). See also
568 Documentation/kdump/kdump.txt for a example.
571 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
576 cs89x0_media= [HW,NET]
577 Format: { rj45 | aui | bnc }
580 See header of drivers/s390/block/dasd_devmap.c.
582 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
583 (one device per port)
584 Format: <port#>,<type>
585 See also Documentation/input/joystick-parport.txt
587 debug [KNL] Enable kernel debugging (events log level).
590 [KNL] verbose self-tests
592 Print debugging info while doing the locking API
594 We default to 0 (no extra messages), setting it to
595 1 will print _a lot_ more information - normally
596 only useful to kernel developers.
598 debug_objects [KNL] Enable object debugging
600 debugpat [X86] Enable PAT debugging
602 decnet.addr= [HW,NET]
603 Format: <area>[,<node>]
604 See also Documentation/networking/decnet.txt.
607 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
608 Change the default blue palette of the console.
609 This is a 16-member array composed of values
613 Format: <green0>,<green1>,<green2>,...,<green15>
614 Change the default green palette of the console.
615 This is a 16-member array composed of values
619 Format: <red0>,<red1>,<red2>,...,<red15>
620 Change the default red palette of the console.
621 This is a 16-member array composed of values
627 Set system-wide default UTF-8 mode for all tty's.
628 Default is 1, i.e. UTF-8 mode is enabled for all
629 newly opened terminals.
632 Set number of hash buckets for dentry cache.
635 IO parameters + enable/disable command.
637 digiepca= [HW,SERIAL]
638 See drivers/char/README.epca and
639 Documentation/serial/digiepca.txt.
641 disable_mtrr_cleanup [X86]
642 enable_mtrr_cleanup [X86]
643 The kernel tries to adjust MTRR layout from continuous
644 to discrete, to make X server driver able to add WB
645 entry later. This parameter enables/disables that.
647 mtrr_chunk_size=nn[KMG] [X86]
648 used for mtrr cleanup. It is largest continous chunk
649 that could hold holes aka. UC entries.
651 mtrr_gran_size=nn[KMG] [X86]
652 Used for mtrr cleanup. It is granularity of mtrr block.
654 Large value could prevent small alignment from
657 mtrr_spare_reg_nr=n [X86]
659 Range: 0,7 : spare reg number
661 Used for mtrr cleanup. It is spare mtrr entries number.
662 Set to 2 or more if your graphical card needs more.
664 disable_mtrr_trim [X86, Intel and AMD only]
665 By default the kernel will trim any uncacheable
666 memory out of your available memory pool based on
667 MTRR settings. This parameter disables that behavior,
668 possibly causing your machine to run very slowly.
670 dmasound= [HW,OSS] Sound subsystem buffers
676 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
678 earlyprintk=serial[,ttySn[,baudrate]]
681 Append ",keep" to not disable it when the real console
684 Only vga or serial or usb debug port at a time.
686 Currently only ttyS0 and ttyS1 are supported.
688 Interaction with the standard serial driver is not
691 The VGA output is eventually overwritten by the real
697 Format: {"off" | "on" | "skip[mbr]"}
699 eisa_irq_edge= [PARISC,HW]
700 See header of drivers/parisc/eisa.c.
703 See comment before function elanfreq_setup() in
704 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
707 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
708 See Documentation/block/as-iosched.txt and
709 Documentation/block/deadline-iosched.txt for details.
711 elfcorehdr= [IA64,PPC,SH,X86-32,X86_64]
712 Specifies physical address of start of kernel core
713 image elf header. Generally kexec loader will
714 pass this option to capture kernel.
715 See Documentation/kdump/kdump.txt for details.
717 enforcing [SELINUX] Set initial enforcing status.
719 See security/selinux/Kconfig help text.
720 0 -- permissive (log only, no denials).
721 1 -- enforcing (deny and log).
723 Value can be changed at runtime via /selinux/enforce.
726 Format: <spdif>,[<nomix>,[<amplifier>]]
727 See also header of sound/oss/es1371.c.
729 ether= [HW,NET] Ethernet cards parameters
730 This option is obsoleted by the "netdev=" option, which
731 has equivalent usage. See its documentation for details.
733 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
738 fail_make_request=[KNL]
739 General fault injection mechanism.
740 Format: <interval>,<probability>,<space>,<times>
741 See also /Documentation/fault-injection/.
744 See header of drivers/scsi/fd_mcs.c.
747 See header of drivers/scsi/fdomain.c.
750 See Documentation/blockdev/floppy.txt.
752 force_pal_cache_flush
753 [IA-64] Avoid check_sal_cache_flush which may hang on
754 buggy SAL_CACHE_FLUSH implementations. Using this
755 parameter will force ia64_sal_cache_flush to call
756 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
759 [ftrace] will set and start the specified tracer
760 as early as possible in order to facilitate early
764 [ftrace] will dump the trace buffers on oops.
767 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
768 support via parallel port (up to 5 devices per port)
769 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
770 See also Documentation/input/joystick-parport.txt
774 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
779 See header of drivers/scsi/gdth.c.
781 gpt [EFI] Forces disk with valid GPT signature but
782 invalid Protective MBR to be treated as GPT.
786 hashdist= [KNL,NUMA] Large hashes allocated during boot
787 are distributed across NUMA nodes. Defaults on
788 for IA-64, off otherwise.
789 Format: 0 | 1 (for off | on)
791 hcl= [IA-64] SGI's Hardware Graph compatibility layer
793 hd= [EIDE] (E)IDE hard drive subsystem geometry
794 Format: <cyl>,<head>,<sect>
796 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
797 size of <nn>. This works even on boxes that have no
798 highmem otherwise. This also works to reduce highmem
799 size on bigger boxes.
801 highres= [KNL] Enable/disable high resolution timer mode.
802 Valid parameters: "on", "off"
806 See Documentation/isdn/README.HiSax.
808 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
809 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
810 On x86-64 and powerpc, this option can be specified
811 multiple times interleaved with hugepages= to reserve
812 huge pages of different sizes. Valid pages sizes on
813 x86-64 are 2M (when the CPU supports "pse") and 1G
814 (when the CPU supports the "pdpe1gb" cpuinfo flag)
815 Note that 1GB pages can only be allocated at boot time
816 using hugepages= and not freed afterwards.
818 [same as hugepagesz=] The size of the default
819 HugeTLB page size. This is the size represented by
820 the legacy /proc/ hugepages APIs, used for SHM, and
821 default size when mounting hugetlbfs filesystems.
822 Defaults to the default architecture's huge page size
827 hvc_iucv= [S390] Number of z/VM IUCV Hypervisor console (HVC)
828 back-ends. Valid parameters: 0..8
830 i8042.debug [HW] Toggle i8042 debug mode
831 i8042.direct [HW] Put keyboard port into non-translated mode
832 i8042.dumbkbd [HW] Pretend that controller can only read data from
833 keyboard and cannot control its state
834 (Don't attempt to blink the leds)
835 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
836 i8042.nokbd [HW] Don't check/create keyboard port
837 i8042.noloop [HW] Disable the AUX Loopback command while probing
839 i8042.nomux [HW] Don't check presence of an active multiplexing
841 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
844 [HW] Frequency with which keyboard LEDs should blink
845 when kernel panics (default is 0.5 sec)
846 i8042.reset [HW] Reset the controller during init and cleanup
847 i8042.unlock [HW] Unlock (ignore) the keylock
851 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
852 indicates that the driver is running on unsupported
854 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
855 does not match list of supported models.
857 [HW] Report power status in /proc/i8k
858 (disabled by default)
859 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
862 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
863 See Documentation/mca.txt.
866 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
868 ide= [HW] (E)IDE subsystem
869 Format: ide=nodma or ide=doubler
870 See Documentation/ide/ide.txt.
872 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
873 See Documentation/ide/ide.txt.
876 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
877 Poll forces a polling idle loop that can slightly improves the performance
878 of waking up a idle CPU, but will use a lot of power and make the system
879 run hot. Not recommended.
880 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
881 to not use it because it doesn't save as much power as a normal idle
882 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
884 idle=halt. Halt is forced to be used for CPU idle.
885 In such case C2/C3 won't be used again.
886 idle=nomwait. Disable mwait for CPU C-states
888 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
889 Claim all unknown PCI IDE storage controllers.
891 ignore_loglevel [KNL]
892 Ignore loglevel setting - this will print /all/
893 kernel messages to the console. Useful for debugging.
896 Set number of hash buckets for inode cache.
899 See header of drivers/scsi/in2000.c.
903 Run specified binary instead of /sbin/init as init
906 initcall_debug [KNL] Trace initcalls as they are executed. Useful
907 for working out where the kernel is dying during
910 initrd= [BOOT] Specify the location of the initial ramdisk
912 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
930 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
932 Disable intel iommu driver.
933 igfx_off [Default Off]
934 By default, gfx is mapped as normal device. If a gfx
935 device has a dedicated DMAR unit, the DMAR unit is
936 bypassed by not enabling DMAR with this option. In
937 this case, gfx device will use physical address for
940 With this option iommu will not optimize to look
941 for io virtual address below 32 bit forcing dual
942 address cycle on pci bus for cards supporting greater
943 than 32 bit addressing. The default is to look
944 for translation below 32 bit and if not available
945 then look in the higher range.
947 With this option on every unmap_single operation will
948 result in a hardware IOTLB flush operation as opposed
949 to batching them for performance.
951 io_delay= [X86-32,X86-64] I/O delay method
953 Standard port 0x80 based delay
955 Alternate port 0xed based delay (needed on some systems)
957 Simple two microseconds delay
961 io7= [HW] IO7 for Marvel based alpha systems
962 See comment before marvel_specify_io7 in
963 arch/alpha/kernel/core_marvel.c.
966 See Documentation/filesystems/nfsroot.txt.
968 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
969 See comment before ip2_setup() in
970 drivers/char/ip2/ip2base.c.
972 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
973 See header of drivers/scsi/ips.c.
975 ports= [IP_VS_FTP] IPVS ftp helper module
977 Up to 8 (IP_VS_APP_MAX_PORTS) ports
979 Format: <port>,<port>....
982 When an interrupt is not handled search all handlers
983 for it. Intended to get systems with badly broken
987 When an interrupt is not handled search all handlers
988 for it. Also check all handlers each timer
989 interrupt. Intended to get systems with badly broken
993 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
995 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
997 <cpu number>,...,<cpu number>
999 <cpu number>-<cpu number>
1000 (must be a positive range in ascending order)
1002 <cpu number>,...,<cpu number>-<cpu number>
1004 This option can be used to specify one or more CPUs
1005 to isolate from the general SMP balancing and scheduling
1006 algorithms. You can move a process onto or off an
1007 "isolated" CPU via the CPU affinity syscalls or cpuset.
1008 <cpu number> begins at 0 and the maximum value is
1009 "number of CPUs in system - 1".
1011 This option is the preferred way to isolate CPUs. The
1012 alternative -- manually setting the CPU mask of all
1013 tasks in the system -- can cause problems and
1014 suboptimal load balancer performance.
1018 js= [HW,JOY] Analog joystick
1019 See Documentation/input/joystick.txt.
1021 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1022 specifies the amount of memory usable by the kernel
1023 for non-movable allocations. The requested amount is
1024 spread evenly throughout all nodes in the system. The
1025 remaining memory in each node is used for Movable
1026 pages. In the event, a node is too small to have both
1027 kernelcore and Movable pages, kernelcore pages will
1028 take priority and other nodes will have a larger number
1029 of kernelcore pages. The Movable zone is used for the
1030 allocation of pages that may be reclaimed or moved
1031 by the page migration subsystem. This means that
1032 HugeTLB pages may not be allocated from this zone.
1033 Note that allocations like PTEs-from-HighMem still
1034 use the HighMem zone if it exists, and the Normal
1035 zone if it does not.
1037 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
1038 is similar to kernelcore except it specifies the
1039 amount of memory used for migratable allocations.
1040 If both kernelcore and movablecore is specified,
1041 then kernelcore will be at *least* the specified
1042 value but may be more. If movablecore on its own
1043 is specified, the administrator must be careful
1044 that the amount of memory usable for all allocations
1049 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1052 kgdboc= [HW] kgdb over consoles.
1053 Requires a tty driver that supports console polling.
1054 (only serial suported for now)
1055 Format: <serial_device>[,baud]
1057 kmac= [MIPS] korina ethernet MAC address.
1058 Configure the RouterBoard 532 series on-chip
1059 Ethernet adapter MAC address.
1065 lapic [X86-32,APIC] Enable the local APIC even if BIOS
1068 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
1071 libata.dma= [LIBATA] DMA control
1072 libata.dma=0 Disable all PATA and SATA DMA
1073 libata.dma=1 PATA and SATA Disk DMA only
1074 libata.dma=2 ATAPI (CDROM) DMA only
1075 libata.dma=4 Compact Flash DMA only
1076 Combinations also work, so libata.dma=3 enables DMA
1077 for disks and CDROMs, but not CFs.
1079 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1083 libata.force= [LIBATA] Force configurations. The format is comma
1084 separated list of "[ID:]VAL" where ID is
1085 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1086 matching port, link or device. Basically, it matches
1087 the ATA ID string printed on console by libata. If
1088 the whole ID part is omitted, the last PORT and DEVICE
1089 values are used. If ID hasn't been specified yet, the
1090 configuration applies to all ports, links and devices.
1092 If only DEVICE is omitted, the parameter applies to
1093 the port and all links and devices behind it. DEVICE
1094 number of 0 either selects the first device or the
1095 first fan-out link behind PMP device. It does not
1096 select the host link. DEVICE number of 15 selects the
1097 host link and device attached to it.
1099 The VAL specifies the configuration to force. As long
1100 as there's no ambiguity shortcut notation is allowed.
1101 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1102 The following configurations can be forced.
1104 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1105 Any ID with matching PORT is used.
1107 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1109 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1110 udma[/][16,25,33,44,66,100,133] notation is also
1113 * [no]ncq: Turn on or off NCQ.
1115 * nohrst, nosrst, norst: suppress hard, soft
1118 If there are multiple matching configurations changing
1119 the same attribute, the last one is used.
1121 load_ramdisk= [RAM] List of ramdisks to load from floppy
1122 See Documentation/blockdev/ramdisk.txt.
1124 lockd.nlm_grace_period=P [NFS] Assign grace period.
1127 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1130 lockd.nlm_timeout=T [NFS] Assign timeout value.
1133 lockd.nlm_udpport=M [NFS] Assign UDP port.
1136 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1139 loglevel= All Kernel Messages with a loglevel smaller than the
1140 console loglevel will be printed to the console. It can
1141 also be changed with klogd or other programs. The
1142 loglevels are defined as follows:
1144 0 (KERN_EMERG) system is unusable
1145 1 (KERN_ALERT) action must be taken immediately
1146 2 (KERN_CRIT) critical conditions
1147 3 (KERN_ERR) error conditions
1148 4 (KERN_WARNING) warning conditions
1149 5 (KERN_NOTICE) normal but significant condition
1150 6 (KERN_INFO) informational
1151 7 (KERN_DEBUG) debug-level messages
1153 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1154 Format: { n | nk | nM }
1155 n must be a power of two. The default size
1156 is set in the kernel config file.
1158 logo.nologo [FB] Disables display of the built-in Linux logo.
1159 This may be used to provide more screen space for
1160 kernel log messages and is useful when debugging
1161 kernel boot problems.
1163 lp=0 [LP] Specify parallel ports to use, e.g,
1164 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1165 lp=reset first parallel port). 'lp=0' disables the
1166 lp=auto printer driver. 'lp=reset' (which can be
1167 specified in addition to the ports) causes
1168 attached printers to be reset. Using
1169 lp=port1,port2,... specifies the parallel ports
1170 to associate lp devices with, starting with
1171 lp0. A port specification may be 'none' to skip
1172 that lp device, or a parport name such as
1173 'parport0'. Specifying 'lp=auto' instead of a
1174 port specification list means that device IDs
1175 from each port should be examined, to see if
1176 an IEEE 1284-compliant printer is attached; if
1177 so, the driver will manage that printer.
1178 See also header of drivers/char/lp.c.
1181 Sets loops_per_jiffy to given constant, thus avoiding
1182 time-consuming boot-time autodetection (up to 250 ms per
1183 CPU). 0 enables autodetection (default). To determine
1184 the correct value for your kernel, boot with normal
1185 autodetection and see what value is printed. Note that
1186 on SMP systems the preset will be applied to all CPUs,
1187 which is likely to cause problems if your CPUs need
1188 significantly divergent settings. An incorrect value
1189 will cause delays in the kernel to be wrong, leading to
1190 unpredictable I/O errors and other breakage. Although
1191 unlikely, in the extreme case this might damage your
1195 Format: <io>,<irq>,<dma>
1197 mac5380= [HW,SCSI] Format:
1198 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1200 machvec= [IA64] Force the use of a particular machine-vector
1201 (machvec) in a generic kernel.
1202 Example: machvec=hpzx1_swiotlb
1204 max_loop= [LOOP] Maximum number of loopback devices that can
1208 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1209 should make use of. maxcpus=n : n >= 0 limits the
1210 kernel to using 'n' processors. n=0 is a special case,
1211 it is equivalent to "nosmp", which also disables
1214 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater than
1215 or equal to this physical address is ignored.
1217 max_luns= [SCSI] Maximum number of LUNs to probe.
1218 Should be between 1 and 2^32-1.
1221 [SCSI] Maximum number of LUNs received.
1222 Should be between 1 and 16384.
1226 mce [X86-32] Machine Check Exception
1228 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1230 md= [HW] RAID subsystems devices and level
1231 See Documentation/md.txt.
1234 Format: <first>,<last>
1235 Specifies range of consoles to be captured by the MDA.
1237 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1238 Amount of memory to be used when the kernel is not able
1239 to see the whole system memory or for test.
1240 [X86-32] Use together with memmap= to avoid physical
1241 address space collisions. Without memmap= PCI devices
1242 could be placed at addresses belonging to unused RAM.
1244 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1248 [KNL,SH] Allow user to override the default size for
1249 per-device physically contiguous DMA buffers.
1251 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1252 E820 memory map, as specified by the user.
1253 Such memmap=exactmap lines can be constructed based on
1254 BIOS output or other requirements. See the memmap=nn@ss
1257 memmap=nn[KMG]@ss[KMG]
1258 [KNL] Force usage of a specific region of memory
1259 Region of memory to be used, from ss to ss+nn.
1261 memmap=nn[KMG]#ss[KMG]
1262 [KNL,ACPI] Mark specific memory as ACPI data.
1263 Region of memory to be used, from ss to ss+nn.
1265 memmap=nn[KMG]$ss[KMG]
1266 [KNL,ACPI] Mark specific memory as reserved.
1267 Region of memory to be used, from ss to ss+nn.
1268 Example: Exclude memory from 0x18690000-0x1869ffff
1269 memmap=64K$0x18690000
1271 memmap=0x10000$0x18690000
1273 memory_corruption_check=0/1 [X86]
1274 Some BIOSes seem to corrupt the first 64k of
1275 memory when doing things like suspend/resume.
1276 Setting this option will scan the memory
1277 looking for corruption. Enabling this will
1278 both detect corruption and prevent the kernel
1279 from using the memory being corrupted.
1280 However, its intended as a diagnostic tool; if
1281 repeatable BIOS-originated corruption always
1282 affects the same memory, you can use memmap=
1283 to prevent the kernel from using that memory.
1285 memory_corruption_check_size=size [X86]
1286 By default it checks for corruption in the low
1287 64k, making this memory unavailable for normal
1288 use. Use this parameter to scan for
1289 corruption in more or less memory.
1291 memory_corruption_check_period=seconds [X86]
1292 By default it checks for corruption every 60
1293 seconds. Use this parameter to check at some
1294 other rate. 0 disables periodic checking.
1296 memtest= [KNL,X86] Enable memtest
1298 range: 0,4 : pattern number
1299 default : 0 <disable>
1301 meye.*= [HW] Set MotionEye Camera parameters
1302 See Documentation/video4linux/meye.txt.
1304 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1305 Multi-Function General Purpose Timers on AMD Geode
1308 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1309 the BIOS has incorrectly applied a workaround. TinyBIOS
1310 version 0.98 is known to be affected, 0.99 fixes the
1311 problem by letting the user disable the workaround.
1315 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1316 physical address is ignored.
1319 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1320 parameter allows control of the logging verbosity for
1321 the additional memory initialisation checks. A value
1322 of 0 disables mminit logging and a level of 4 will
1323 log everything. Information is printed at KERN_DEBUG
1324 so loglevel=8 may also need to be specified.
1327 [MOUSE] Maximum time between finger touching and
1328 leaving touchpad surface for touch to be considered
1329 a tap and be reported as a left button click (for
1330 touchpads working in absolute mode only).
1332 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1333 reporting absolute coordinates, such as tablets
1334 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1335 reporting absolute coordinates, such as tablets
1340 MTD_Partition= [MTD]
1341 Format: <name>,<region-number>,<size>,<offset>
1343 MTD_Region= [MTD] Format:
1344 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1347 See drivers/mtd/cmdlinepart.c.
1350 ARM/S3C2412 JIVE boot control
1352 See arch/arm/mach-s3c2412/mach-jive.c
1354 mtouchusb.raw_coordinates=
1355 [HW] Make the MicroTouch USB driver use raw coordinates
1356 ('y', default) or cooked coordinates ('n')
1358 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1361 See header of drivers/scsi/NCR_D700.c.
1365 ncr53c400= [HW,SCSI]
1367 ncr53c400a= [HW,SCSI]
1369 ncr53c406a= [HW,SCSI]
1371 ncr53c8xx= [HW,SCSI]
1373 netdev= [NET] Network devices parameters
1374 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1375 Note that mem_start is often overloaded to mean
1376 something different and driver-specific.
1377 This usage is only documented in each driver source
1381 [NETFILTER] Enable connection tracking flow accounting
1382 0 to disable accounting
1383 1 to enable accounting
1384 Default value depends on CONFIG_NF_CT_ACCT that is
1385 going to be removed in 2.6.29.
1388 See Documentation/filesystems/nfsroot.txt.
1390 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1391 See Documentation/filesystems/nfsroot.txt.
1393 nfs.callback_tcpport=
1394 [NFS] set the TCP port on which the NFSv4 callback
1395 channel should listen.
1397 nfs.idmap_cache_timeout=
1398 [NFS] set the maximum lifetime for idmapper cache
1402 [NFS] enable 64-bit inode numbers.
1403 If zero, the NFS client will fake up a 32-bit inode
1404 number for the readdir() and stat() syscalls instead
1405 of returning the full 64-bit number.
1406 The default is to return 64-bit inode numbers.
1408 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1409 when a NMI is triggered.
1410 Format: [state][,regs][,debounce][,die]
1412 nmi_watchdog= [KNL,BUGS=X86-32,X86-64] Debugging features for SMP kernels
1413 Format: [panic,][num]
1415 0 - turn nmi_watchdog off
1416 1 - use the IO-APIC timer for the NMI watchdog
1417 2 - use the local APIC for the NMI watchdog using
1418 a performance counter. Note: This will use one performance
1419 counter and the local APIC's performance vector.
1420 When panic is specified panic when an NMI watchdog timeout occurs.
1421 This is useful when you use a panic=... timeout and need the box
1423 Instead of 1 and 2 it is possible to use the following
1424 symbolic names: lapic and ioapic
1425 Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
1427 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1428 emulation library even if a 387 maths coprocessor
1431 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1432 caches in the slab allocator. Saves per-node memory,
1433 but will impact performance.
1437 noapic [SMP,APIC] Tells the kernel to not make use of any
1438 IOAPICs that may be present in the system.
1440 nobats [PPC] Do not use BATs for mapping kernel lowmem
1441 on "Classic" PPC cores.
1445 nodelayacct [KNL] Disable per-task delay accounting
1447 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1449 nodsp [SH] Disable hardware DSP at boot time.
1451 noefi [X86-32,X86-64] Disable EFI runtime services support.
1455 noexec [X86-32,X86-64]
1456 On X86-32 available only on PAE configured kernels.
1457 noexec=on: enable non-executable mappings (default)
1458 noexec=off: disable non-executable mappings
1461 This affects only 32-bit executables.
1462 noexec32=on: enable non-executable mappings (default)
1463 read doesn't imply executable mappings
1464 noexec32=off: disable non-executable mappings
1465 read implies executable mappings
1467 nofpu [SH] Disable hardware FPU at boot time.
1469 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1470 register save and restore. The kernel will only save
1471 legacy floating-point registers on task switch.
1473 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1477 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1478 instruction doesn't work correctly and not to
1481 no_file_caps Tells the kernel not to honor file capabilities. The
1482 only way then for a file to be executed with privilege
1483 is to be setuid root or executed by root.
1485 nohalt [IA-64] Tells the kernel not to use the power saving
1486 function PAL_HALT_LIGHT when idle. This increases
1487 power-consumption. On the positive side, it reduces
1488 interrupt wake-up latency, which may improve performance
1489 in certain environments such as networked servers or
1492 nohz= [KNL] Boottime enable/disable dynamic ticks
1493 Valid arguments: on, off
1496 noirqdebug [X86-32] Disables the code which attempts to detect and
1497 disable unhandled interrupt sources.
1499 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1500 broken timer IRQ sources.
1502 noisapnp [ISAPNP] Disables ISA PnP code.
1504 noinitrd [RAM] Tells the kernel not to load any configured
1509 nojitter [IA64] Disables jitter checking for ITC timers.
1511 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1513 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1515 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1517 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1518 default x2apic cluster mode on platforms
1521 noltlbs [PPC] Do not use large page/tlb entries for kernel
1522 lowmem mapping on PPC40x.
1524 nomca [IA-64] Disable machine check abort handling
1526 nomce [X86-32] Machine Check Exception
1528 nomfgpt [X86-32] Disable Multi-Function General Purpose
1529 Timer usage (for AMD Geode machines).
1531 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1533 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1534 with UP alternatives
1536 noresidual [PPC] Don't use residual data on PReP machines.
1538 noresume [SWSUSP] Disables resume and restores original swap
1541 no-scroll [VGA] Disables scrollback.
1542 This is required for the Braillex ib80-piezo Braille
1543 reader made by F.H. Papenmeier (Germany).
1547 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1549 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1550 and disable the IO APIC. legacy for "maxcpus=0".
1552 nosoftlockup [KNL] Disable the soft-lockup detector.
1554 nosync [HW,M68K] Disables sync negotiation for all devices.
1556 notsc [BUGS=X86-32] Disable Time Stamp Counter
1558 nousb [USB] Disable the USB subsystem
1562 nptcg= [IA64] Override max number of concurrent global TLB
1563 purges which is reported from either PAL_VM_SUMMARY or
1566 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1567 one of ['zone', 'node', 'default'] can be specified
1568 This can be set from sysctl after boot.
1569 See Documentation/sysctl/vm.txt for details.
1571 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1573 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1574 Rather than timing out after 20 ms if an EC
1575 command is not properly ACKed, override the length
1576 of the timeout. We have interrupts disabled while
1577 waiting for the ACK, so if this is set too high
1578 interrupts *may* be lost!
1583 oprofile.timer= [HW]
1584 Use timer interrupt instead of performance counters
1586 osst= [HW,SCSI] SCSI Tape Driver
1587 Format: <buffer_size>,<write_threshold>
1588 See also Documentation/scsi/st.txt.
1590 panic= [KNL] Kernel behaviour on panic
1593 parkbd.port= [HW] Parallel port number the keyboard adapter is
1594 connected to, default is 0.
1596 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1597 0 for XT, 1 for AT (default is AT).
1600 parport= [HW,PPT] Specify parallel ports. 0 disables.
1601 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1602 Use 'auto' to force the driver to use any
1603 IRQ/DMA settings detected (the default is to
1604 ignore detected IRQ/DMA settings because of
1605 possible conflicts). You can specify the base
1606 address, IRQ, and DMA settings; IRQ and DMA
1607 should be numbers, or 'auto' (for using detected
1608 settings on that particular port), or 'nofifo'
1609 (to avoid using a FIFO even if it is detected).
1610 Parallel ports are assigned in the order they
1611 are specified on the command line, starting
1614 parport_init_mode= [HW,PPT]
1615 Configure VIA parallel port to operate in
1616 a specific mode. This is necessary on Pegasos
1617 computer where firmware has no options for setting
1618 up parallel port mode and sets it to spp.
1619 Currently this function knows 686a and 8231 chips.
1620 Format: [spp|ps2|epp|ecp|ecpepp]
1622 pas2= [HW,OSS] Format:
1623 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1626 See header of drivers/scsi/pas16.c.
1629 Halt all CPUs after the first oops has been printed for
1630 the specified number of seconds. This is to be used if
1631 your oopses keep scrolling off the screen.
1636 See header of drivers/block/paride/pcd.c.
1637 See also Documentation/blockdev/paride.txt.
1639 pci=option[,option...] [PCI] various PCI subsystem options:
1640 off [X86] don't probe for the PCI bus
1641 bios [X86-32] force use of PCI BIOS, don't access
1642 the hardware directly. Use this if your machine
1643 has a non-standard PCI host bridge.
1644 nobios [X86-32] disallow use of PCI BIOS, only direct
1645 hardware access methods are allowed. Use this
1646 if you experience crashes upon bootup and you
1647 suspect they are caused by the BIOS.
1648 conf1 [X86] Force use of PCI Configuration
1650 conf2 [X86] Force use of PCI Configuration
1652 noaer [PCIE] If the PCIEAER kernel config parameter is
1653 enabled, this kernel boot option can be used to
1654 disable the use of PCIE advanced error reporting.
1655 nodomains [PCI] Disable support for multiple PCI
1656 root domains (aka PCI segments, in ACPI-speak).
1657 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1659 nomsi [MSI] If the PCI_MSI kernel config parameter is
1660 enabled, this kernel boot option can be used to
1661 disable the use of MSI interrupts system-wide.
1662 noioapicquirk [APIC] Disable all boot interrupt quirks.
1663 Safety option to keep boot IRQs enabled. This
1664 should never be necessary.
1665 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1666 primary IO-APIC for bridges that cannot disable
1667 boot IRQs. This fixes a source of spurious IRQs
1668 when the system masks IRQs.
1669 noioapicreroute [APIC] Disable workaround that uses the
1670 boot IRQ equivalent of an IRQ that connects to
1671 a chipset where boot IRQs cannot be disabled.
1672 The opposite of ioapicreroute.
1673 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1674 routing table. These calls are known to be buggy
1675 on several machines and they hang the machine
1676 when used, but on other computers it's the only
1677 way to get the interrupt routing table. Try
1678 this option if the kernel is unable to allocate
1679 IRQs or discover secondary PCI buses on your
1681 rom [X86] Assign address space to expansion ROMs.
1682 Use with caution as certain devices share
1683 address decoders between ROMs and other
1685 norom [X86] Do not assign address space to
1686 expansion ROMs that do not already have
1687 BIOS assigned address ranges.
1688 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
1689 assigned automatically to PCI devices. You can
1690 make the kernel exclude IRQs of your ISA cards
1692 pirqaddr=0xAAAAA [X86] Specify the physical address
1693 of the PIRQ table (normally generated
1694 by the BIOS) if it is outside the
1695 F0000h-100000h range.
1696 lastbus=N [X86] Scan all buses thru bus #N. Can be
1697 useful if the kernel is unable to find your
1698 secondary buses and you want to tell it
1699 explicitly which ones they are.
1700 assign-busses [X86] Always assign all PCI bus
1701 numbers ourselves, overriding
1702 whatever the firmware may have done.
1703 usepirqmask [X86] Honor the possible IRQ mask stored
1704 in the BIOS $PIR table. This is needed on
1705 some systems with broken BIOSes, notably
1706 some HP Pavilion N5400 and Omnibook XE3
1707 notebooks. This will have no effect if ACPI
1708 IRQ routing is enabled.
1709 noacpi [X86] Do not use ACPI for IRQ routing
1710 or for PCI scanning.
1711 use_crs [X86] Use _CRS for PCI resource
1713 routeirq Do IRQ routing for all PCI devices.
1714 This is normally done in pci_enable_device(),
1715 so this option is a temporary workaround
1716 for broken drivers that don't call it.
1717 skip_isa_align [X86] do not align io start addr, so can
1718 handle more pci cards
1719 firmware [ARM] Do not re-enumerate the bus but instead
1720 just use the configuration from the
1721 bootloader. This is currently used on
1722 IXP2000 systems where the bus has to be
1723 configured a certain way for adjunct CPUs.
1724 noearly [X86] Don't do any early type 1 scanning.
1725 This might help on some broken boards which
1726 machine check when some devices' config space
1727 is read. But various workarounds are disabled
1728 and some IOMMU drivers will not work.
1729 bfsort Sort PCI devices into breadth-first order.
1730 This sorting is done to get a device
1731 order compatible with older (<= 2.4) kernels.
1732 nobfsort Don't sort PCI devices into breadth-first order.
1733 cbiosize=nn[KMG] The fixed amount of bus space which is
1734 reserved for the CardBus bridge's IO window.
1735 The default value is 256 bytes.
1736 cbmemsize=nn[KMG] The fixed amount of bus space which is
1737 reserved for the CardBus bridge's memory
1738 window. The default value is 64 megabytes.
1740 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1743 force Enable ASPM even on devices that claim not to support it.
1744 WARNING: Forcing ASPM on may cause system lockups.
1746 pcmv= [HW,PCMCIA] BadgePAD 4
1749 See Documentation/blockdev/paride.txt.
1751 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1754 See arch/parisc/kernel/pdc_chassis.c
1757 See Documentation/blockdev/paride.txt.
1760 See Documentation/blockdev/paride.txt.
1762 pirq= [SMP,APIC] Manual mp-table setup
1763 See Documentation/x86/i386/IO-APIC.txt.
1765 plip= [PPT,NET] Parallel port network link
1766 Format: { parport<nr> | timid | 0 }
1767 See also Documentation/parport.txt.
1769 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1770 Override pmtimer IOPort with a hex value.
1774 Enable PNP debug messages. This depends on the
1775 CONFIG_PNP_DEBUG_MESSAGES option.
1781 { on | off | curr | res | no-curr | no-res }
1784 [ISAPNP] Exclude IRQs for the autoconfiguration
1787 [ISAPNP] Exclude DMAs for the autoconfiguration
1789 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1790 Ranges are in pairs (I/O port base and size).
1793 [ISAPNP] Exclude memory regions for the
1795 Ranges are in pairs (memory base and size).
1798 Enables pr_debug()/dev_dbg() calls if
1799 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1800 be switched on/off via <debugfs>/dynamic_printk/modules
1802 print-fatal-signals=
1803 [KNL] debug: print fatal signals
1804 print-fatal-signals=1: print segfault info to
1808 printk.time= Show timing data prefixed to each printk message line
1809 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1811 profile= [KNL] Enable kernel profiling via /proc/profile
1812 Format: [schedule,]<number>
1813 Param: "schedule" - profile schedule points.
1814 Param: <number> - step/bucket size as a power of 2 for
1815 statistical time based profiling.
1816 Param: "sleep" - profile D-state sleeping (millisecs).
1817 Requires CONFIG_SCHEDSTATS
1818 Param: "kvm" - profile VM exits.
1820 processor.max_cstate= [HW,ACPI]
1821 Limit processor to maximum C-state
1822 max_cstate=9 overrides any DMI blacklist limit.
1824 processor.nocst [HW,ACPI]
1825 Ignore the _CST method to determine C-states,
1826 instead using the legacy FADT method
1828 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1830 See Documentation/blockdev/ramdisk.txt.
1832 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1833 probe for; one of (bare|imps|exps|lifebook|any).
1834 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1836 psmouse.resetafter= [HW,MOUSE]
1837 Try to reset the device after so many bad packets
1840 [HW,MOUSE] Set desired mouse resolution, in dpi.
1841 psmouse.smartscroll=
1842 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1843 0 = disabled, 1 = enabled (default).
1845 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1847 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1850 See Documentation/blockdev/paride.txt.
1853 [KNL] Number of legacy pty's. Overwrites compiled-in
1856 quiet [KNL] Disable most log messages
1861 See Documentation/md.txt.
1863 ramdisk_blocksize= [RAM]
1864 See Documentation/blockdev/ramdisk.txt.
1866 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1867 See Documentation/blockdev/ramdisk.txt.
1869 rcupdate.blimit= [KNL,BOOT]
1870 Set maximum number of finished RCU callbacks to process
1873 rcupdate.qhimark= [KNL,BOOT]
1874 Set threshold of queued
1875 RCU callbacks over which batch limiting is disabled.
1877 rcupdate.qlowmark= [KNL,BOOT]
1878 Set threshold of queued RCU callbacks below which
1879 batch limiting is re-enabled.
1883 Run specified binary instead of /init from the ramdisk,
1884 used for early userspace startup. See initrd.
1886 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1887 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1888 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1891 [KNL, SMP] Set scheduler's default relax_domain_level.
1892 See Documentation/cpusets.txt.
1894 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1896 reservetop= [X86-32]
1898 Reserves a hole at the top of the kernel virtual
1901 reset_devices [KNL] Force drivers to reset the underlying device
1902 during initialization.
1905 Specify the partition device for software suspend
1907 resume_offset= [SWSUSP]
1908 Specify the offset from the beginning of the partition
1909 given by "resume=" at which the swap header is located,
1910 in <PAGE_SIZE> units (needed only for swap files).
1911 See Documentation/power/swsusp-and-swap-files.txt
1913 retain_initrd [RAM] Keep initrd memory after extraction
1915 rhash_entries= [KNL,NET]
1916 Set number of hash buckets for route cache
1918 riscom8= [HW,SERIAL]
1919 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1921 ro [KNL] Mount root device read-only on boot
1923 root= [KNL] Root filesystem
1925 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1926 mount the root filesystem
1928 rootflags= [KNL] Set root filesystem mount option string
1930 rootfstype= [KNL] Set root filesystem type
1932 rootwait [KNL] Wait (indefinitely) for root device to show up.
1933 Useful for devices that are detected asynchronously
1934 (e.g. USB and MMC devices).
1936 root_plug.vendor_id=
1937 [ROOTPLUG] Override the default vendor ID
1939 root_plug.product_id=
1940 [ROOTPLUG] Override the default product ID
1943 [ROOTPLUG] Enable debugging output
1945 rw [KNL] Mount root device read-write on boot
1947 S [KNL] Run init in single mode
1950 See drivers/net/irda/sa1100_ir.c.
1952 sbni= [NET] Granch SBNI12 leased line adapter
1954 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1955 Format: <io>[,<timeout>[,<isapnp>]]
1957 scsi_debug_*= [SCSI]
1958 See drivers/scsi/scsi_debug.c.
1960 scsi_default_dev_flags=
1961 [SCSI] SCSI default device flags
1964 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1965 Format: <vendor>:<model>:<flags>
1966 (flags are integer value)
1968 scsi_logging_level= [SCSI] a bit mask of logging levels
1969 See drivers/scsi/scsi_logging.h for bits. Also
1970 settable via sysctl at dev.scsi.logging_level
1971 (/proc/sys/dev/scsi/logging_level).
1972 There is also a nice 'scsi_logging_level' script in the
1973 S390-tools package, available for download at
1974 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1976 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1977 discovered. async scans them in kernel threads,
1978 allowing boot to proceed. none ignores them, expecting
1979 user space to do the scan.
1981 selinux [SELINUX] Disable or enable SELinux at boot time.
1982 Format: { "0" | "1" }
1983 See security/selinux/Kconfig help text.
1986 Default value is set via kernel config option.
1987 If enabled at boot time, /selinux/disable can be used
1988 later to disable prior to initial policy load.
1990 selinux_compat_net =
1991 [SELINUX] Set initial selinux_compat_net flag value.
1992 Format: { "0" | "1" }
1993 0 -- use new secmark-based packet controls
1994 1 -- use legacy packet controls
1995 Default value is 0 (preferred).
1996 Value can be changed at runtime via
1997 /selinux/compat_net.
1999 serialnumber [BUGS=X86-32]
2002 Maximal number of shapers.
2004 show_msr= [x86] show boot-time MSR settings
2005 Format: { <integer> }
2006 Show boot-time (BIOS-initialized) MSR settings.
2007 The parameter means the number of CPUs to show,
2008 for example 1 means boot CPU only.
2011 See header of drivers/scsi/sim710.c.
2018 slub_debug[=options[,slabs]] [MM, SLUB]
2019 Enabling slub_debug allows one to determine the
2020 culprit if slab objects become corrupted. Enabling
2021 slub_debug can create guard zones around objects and
2022 may poison objects when not in use. Also tracks the
2023 last alloc / free. For more information see
2024 Documentation/vm/slub.txt.
2026 slub_max_order= [MM, SLUB]
2027 Determines the maximum allowed order for slabs.
2028 A high setting may cause OOMs due to memory
2029 fragmentation. For more information see
2030 Documentation/vm/slub.txt.
2032 slub_min_objects= [MM, SLUB]
2033 The minimum number of objects per slab. SLUB will
2034 increase the slab order up to slub_max_order to
2035 generate a sufficiently large slab able to contain
2036 the number of objects indicated. The higher the number
2037 of objects the smaller the overhead of tracking slabs
2038 and the less frequently locks need to be acquired.
2039 For more information see Documentation/vm/slub.txt.
2041 slub_min_order= [MM, SLUB]
2042 Determines the mininum page order for slabs. Must be
2043 lower than slub_max_order.
2044 For more information see Documentation/vm/slub.txt.
2046 slub_nomerge [MM, SLUB]
2047 Disable merging of slabs with similar size. May be
2048 necessary if there is some reason to distinguish
2049 allocs to different slabs. Debug options disable
2050 merging on their own.
2051 For more information see Documentation/vm/slub.txt.
2054 Format: <io1>[,<io2>[,...,<io8>]]
2056 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
2057 attempt to substitute SMP alternatives once at boot.
2059 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2060 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2061 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2062 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2063 smsc-ircc2.ircc_irq= [HW] IRQ line
2064 smsc-ircc2.ircc_dma= [HW] DMA channel
2065 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2066 0: Toshiba Satellite 1800 (GP data pin select)
2067 1: Fast pin select (default)
2070 snd-ad1816a= [HW,ALSA]
2072 snd-ad1848= [HW,ALSA]
2074 snd-ali5451= [HW,ALSA]
2076 snd-als100= [HW,ALSA]
2078 snd-als4000= [HW,ALSA]
2080 snd-azt2320= [HW,ALSA]
2082 snd-cmi8330= [HW,ALSA]
2084 snd-cmipci= [HW,ALSA]
2086 snd-cs4231= [HW,ALSA]
2088 snd-cs4232= [HW,ALSA]
2090 snd-cs4236= [HW,ALSA]
2092 snd-cs4281= [HW,ALSA]
2094 snd-cs46xx= [HW,ALSA]
2096 snd-dt019x= [HW,ALSA]
2098 snd-dummy= [HW,ALSA]
2100 snd-emu10k1= [HW,ALSA]
2102 snd-ens1370= [HW,ALSA]
2104 snd-ens1371= [HW,ALSA]
2106 snd-es968= [HW,ALSA]
2108 snd-es1688= [HW,ALSA]
2110 snd-es18xx= [HW,ALSA]
2112 snd-es1938= [HW,ALSA]
2114 snd-es1968= [HW,ALSA]
2116 snd-fm801= [HW,ALSA]
2118 snd-gusclassic= [HW,ALSA]
2120 snd-gusextreme= [HW,ALSA]
2122 snd-gusmax= [HW,ALSA]
2126 snd-ice1712= [HW,ALSA]
2128 snd-intel8x0= [HW,ALSA]
2130 snd-interwave= [HW,ALSA]
2135 snd-korg1212= [HW,ALSA]
2137 snd-maestro3= [HW,ALSA]
2139 snd-mpu401= [HW,ALSA]
2141 snd-mtpav= [HW,ALSA]
2143 snd-nm256= [HW,ALSA]
2145 snd-opl3sa2= [HW,ALSA]
2153 snd-opti93x= [HW,ALSA]
2157 snd-rme32= [HW,ALSA]
2159 snd-rme96= [HW,ALSA]
2161 snd-rme9652= [HW,ALSA]
2167 snd-sbawe= [HW,ALSA]
2169 snd-serial= [HW,ALSA]
2171 snd-sgalaxy= [HW,ALSA]
2173 snd-sonicvibes= [HW,ALSA]
2178 snd-sun-cs4231= [HW,ALSA]
2180 snd-trident= [HW,ALSA]
2182 snd-usb-audio= [HW,ALSA,USB]
2184 snd-via82xx= [HW,ALSA]
2186 snd-virmidi= [HW,ALSA]
2188 snd-wavefront= [HW,ALSA]
2190 snd-ymfpci= [HW,ALSA]
2193 [KNL] Should the soft-lockup detector generate panics.
2195 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2196 See Documentation/sonypi.txt
2198 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2199 See Documentation/serial/specialix.txt.
2201 spia_io_base= [HW,MTD]
2207 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
2209 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2210 See Documentation/scsi/st.txt.
2213 Enabled the stack tracer on boot up.
2217 Set the STI (builtin display/keyboard on the HP-PARISC
2218 machines) console (graphic card) which should be used
2219 as the initial boot-console.
2220 See also comment in drivers/video/console/sticore.c.
2223 See comment in drivers/video/console/sticore.c.
2226 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2230 Control how the NFS server code allocates CPUs to
2231 service thread pools. Depending on how many NICs
2232 you have and where their interrupts are bound, this
2233 option will affect which CPUs will do NFS serving.
2234 Note: this parameter cannot be changed while the
2235 NFS server is running.
2237 auto the server chooses an appropriate mode
2238 automatically using heuristics
2239 global a single global pool contains all CPUs
2240 percpu one pool for each CPU
2241 pernode one pool for each NUMA node (equivalent
2242 to global on non-NUMA machines)
2244 swiotlb= [IA-64] Number of I/O TLB slabs
2248 sym53c416= [HW,SCSI]
2249 See header of drivers/scsi/sym53c416.c.
2251 sysrq_always_enabled
2253 Ignore sysrq setting - this boot parameter will
2254 neutralize any effect of /proc/sys/kernel/sysrq.
2255 Useful for debugging.
2258 See header of drivers/scsi/t128.c.
2262 test_suspend= [SUSPEND]
2263 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2264 standby suspend) as the system sleep state to briefly
2265 enter during system startup. The system is woken from
2266 this state using a wakeup-capable RTC alarm.
2268 thash_entries= [KNL,NET]
2269 Set number of hash buckets for TCP connection
2271 thermal.act= [HW,ACPI]
2272 -1: disable all active trip points in all thermal zones
2273 <degrees C>: override all lowest active trip points
2275 thermal.crt= [HW,ACPI]
2276 -1: disable all critical trip points in all thermal zones
2277 <degrees C>: override all critical trip points
2279 thermal.nocrt= [HW,ACPI]
2280 Set to disable actions on ACPI thermal zone
2281 critical and hot trip points.
2283 thermal.off= [HW,ACPI]
2284 1: disable ACPI thermal control
2286 thermal.psv= [HW,ACPI]
2287 -1: disable all passive trip points
2288 <degrees C>: override all passive trip points to this value
2290 thermal.tzp= [HW,ACPI]
2291 Specify global default ACPI thermal zone polling rate
2292 <deci-seconds>: poll all this frequency
2293 0: no polling (default)
2296 See comment before function dc390_setup() in
2297 drivers/scsi/tmscsim.c.
2301 Specify if the kernel should make use of the cpu
2302 topology informations if the hardware supports these.
2303 The scheduler will make use of these informations and
2304 e.g. base its process migration decisions on it.
2309 trix= [HW,OSS] MediaTrix AudioTrix Pro
2311 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2313 tsc= Disable clocksource-must-verify flag for TSC.
2315 [x86] reliable: mark tsc clocksource as reliable, this
2316 disables clocksource verification at runtime.
2317 Used to enable high-resolution timer mode on older
2318 hardware, and in virtualized environment.
2320 turbografx.map[2|3]= [HW,JOY]
2321 TurboGraFX parallel port interface
2323 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2324 See also Documentation/input/joystick-parport.txt
2326 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2327 See header of drivers/scsi/u14-34f.c.
2336 [USB] Ignore overcurrent events (default N).
2337 Some badly-designed motherboards generate lots of
2338 bogus events, for ports that aren't wired to
2339 anything. Set this parameter to avoid log spamming.
2340 Note that genuine overcurrent events won't be
2345 Set unknown_nmi_panic=1 early on boot.
2347 usbcore.autosuspend=
2348 [USB] The autosuspend time delay (in seconds) used
2349 for newly-detected USB devices (default 2). This
2350 is the time required before an idle device will be
2351 autosuspended. Devices for which the delay is set
2352 to a negative value won't be autosuspended at all.
2354 usbcore.usbfs_snoop=
2355 [USB] Set to log all usbfs traffic (default 0 = off).
2357 usbcore.blinkenlights=
2358 [USB] Set to cycle leds on hubs (default 0 = off).
2360 usbcore.old_scheme_first=
2361 [USB] Start with the old device initialization
2362 scheme (default 0 = off).
2364 usbcore.use_both_schemes=
2365 [USB] Try the other device initialization scheme
2366 if the first one fails (default 1 = enabled).
2368 usbcore.initial_descriptor_timeout=
2369 [USB] Specifies timeout for the initial 64-byte
2370 USB_REQ_GET_DESCRIPTOR request in milliseconds
2371 (default 5000 = 5.0 seconds).
2374 [USBHID] The interval which mice are to be polled at.
2376 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2377 kernel's map of available physical RAM.
2379 vdso= [X86-32,SH,x86-64]
2380 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2381 vdso=1: enable VDSO (default)
2382 vdso=0: disable VDSO mapping
2384 vdso32= [X86-32,X86-64]
2385 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2386 vdso32=1: enable 32-bit VDSO (default)
2387 vdso32=0: disable 32-bit VDSO mapping
2390 vector=percpu: enable percpu vector domain
2392 video= [FB] Frame buffer configuration
2393 See Documentation/fb/modedb.txt.
2395 vga= [BOOT,X86-32] Select a particular video mode
2396 See Documentation/x86/i386/boot.txt and
2397 Documentation/svga.txt.
2398 Use vga=ask for menu.
2399 This is actually a boot loader parameter; the value is
2400 passed to the kernel using a special protocol.
2402 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2403 size of <nn>. This can be used to increase the
2404 minimum size (128MB on x86). It can also be used to
2405 decrease the size and leave more room for directly
2408 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2411 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2414 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2417 waveartist= [HW,OSS]
2418 Format: <io>,<irq>,<dma>,<dma2>
2421 See header of drivers/scsi/wd33c93.c.
2424 See header of drivers/scsi/wd7000.c.
2427 See Documentation/watchdog/wdt.txt.
2429 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2430 xd_geo= See header of drivers/block/xd.c.
2432 xirc2ps_cs= [NET,PCMCIA]
2434 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2436 norandmaps Don't use address space randomization
2437 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2439 ______________________________________________________________________
2443 Add documentation for ALSA options.
2444 Add more DRM drivers.
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob